JPH10274006A - Drain pipe system - Google Patents

Abstract

(57) [Summary] [PROBLEMS] Assuming economically advantageous U-seal piping, it is possible to secure a U-seal without having to employ a large-sized drain pipe, and at the time of plant startup or sudden pressure in a cooler. Provided is a drain pipe system capable of preventing U seal from breaking due to fluctuation. A cooler for steam cooling provided in a steam turbine plant and a condenser for condensing steam turbine exhaust having a lower internal pressure than the cooler are lower than the water level in the condenser. Are connected by a U-shaped drain pipe 15 having a pipe section of. The cooler 1 is provided through the drain pipe 15.
From 1, the drain is supplied to the condenser 16. A gas / water separator 18 is provided in the middle of the drain pipe 15 to discharge gas to the outside of the drain pipe 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a drain pipe system applied to, for example, a drain pipe for supplying a drain discharged from an aftercooler of a geothermal power plant to a condenser. The present invention relates to a drain pipe system capable of achieving cost reduction, effective use of space, and the like.

[0002]

2. Description of the Related Art For example, in a geothermal power plant, an aftercooler is provided for cooling steam and gas and releasing the cooled gas and air to the atmosphere. It is supplied to the water tank via a drain pipe. In this case, since the internal pressure of the aftercooler is higher than the internal pressure of the condenser, as a method of designing a drain pipe connecting such containers having different pressures,
In order to ensure the specified pressure and flow rate of each container, a system connected via a control valve in the middle of the drain pipe and a U-shaped drain pipe having a pipe lower than the water level in the condenser are used. A system for connecting via a so-called U-seal is known.

FIG. 4 is a system diagram showing a conventional system connected via a control valve.

In the system shown in FIG. 4, steam, gas, water, and the like flowing into the aftercooler 1 through the steam / gas pipe 2 are cooled by water flowing through the cooling water pipe 3, and the steam and the like are cooled. The air is discharged from the atmosphere discharge pipe 4 to the atmosphere as a vent, and the drain is supplied to the condenser 6 via the drain pipe 5. A water level controller 7 is provided in the drain pipe 5, and the opening of the water level controller 7 is controlled by a cooler water level meter 8 provided in the aftercooler 1.
The water level of the drain 9 a in the aftercooler is maintained higher than the water level of the drain in the condenser 6.

[0005] For example, the internal pressure of the aftercooler 1 is 1.08 kg / cm ² , and the internal pressure of the condenser 6 is 0.136.
The pressure difference is set to kg / cm ² , and the pressure difference causes drain supply from the aftercooler 1 to the condenser 6 via the drain pipe 5. In the drain pipe 5, the internal pressure of the aftercooler 1 and the internal pressure of the condenser 6 are separated by the water level adjusting valve 7, and the flow rate is controlled so that a constant water level is maintained in the aftercooler 1.

FIG. 5 is a system diagram showing a conventional system connected through a U-seal.

In the system shown in FIG. 5, the aftercooler 1 and the condenser 6 are connected to a U-shaped drain pipe 5 having a pipe section 5b lower than the water level of the drain 9b in the condenser 6.
The drain is supplied from the aftercooler 1 to the condenser 6 via the drain pipe 5, and the drain is stored while always maintaining a constant drain water level in the lower pipe section 5b. It has become.

In this system, the operation can be continued by separating the internal pressure of the aftercooler 1 and the internal pressure of the condenser 6 by the U-seal function by the drain pipe 5 in the same manner as described above. For example, in the drain tube 5, the Froude number is set to 0.3 or less.

The Froude number is determined by the following equation.

[0010]

(Equation 1)

[0011]

In the prior art described above, when the water level control valve 7 shown in FIG. 4 is installed, the volume of the cooler must be increased in order to store the drain in the aftercooler 1. In addition, the structure of the water level control valve 7 itself is complicated and costly, which is economically disadvantageous.

Also, in FIG.
When the drain pipe 5 having a sealing function is installed, a pit having a large diameter and a depth of, for example, 10 m or more for the lower pipe section 5a is dug to a size in consideration of maintainability. There must be. For this reason, the cost of civil engineering work and the like may increase, and the inspection and maintenance in the power plant may be reduced, or a malfunction such as the U seal may be broken due to pressure fluctuation in the cooler may occur.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a U-seal pipe without using a large-sized drain pipe on the premise of an economically advantageous U-seal pipe. Another object of the present invention is to provide a drain pipe system capable of preventing the U seal from being broken due to pressure fluctuation in the cooler at the time of starting the plant or suddenly.

[0014]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a cooler for steam cooling provided in a steam turbine plant, and a condenser for condensing steam turbine exhaust having a lower internal pressure than the cooler. And a condenser connected to the condenser by a U-shaped drain pipe having a pipe section lower than the water level in the condenser, and a drain from the cooler to the condenser through the drain pipe. A drain pipe system, wherein a steam-water separator is provided in the middle of the drain pipe to discharge gas to the outside of the drain pipe.

According to the second aspect of the present invention, the cooler for steam cooling provided in the steam turbine plant and the condenser for condensing the steam turbine exhaust having an internal pressure lower than that of the cooler are provided with a water level in the condenser. A drain pipe system connected by a U-shaped drain pipe having a lower pipe section, and supplying the drain from the cooler to the condenser through the drain pipe. A drain pipe system characterized by storing drain while maintaining the above water level.

According to the third aspect of the present invention, the cooler for steam cooling provided in the steam turbine plant and the condenser for condensing the steam turbine exhaust having a lower internal pressure than the cooler are connected with the water level in the condenser. A drain pipe system connected by a U-shaped drain pipe having a lower pipe portion and supplying the drain from the cooler to the condenser through the drain pipe, wherein a condenser inlet portion of the drain pipe is provided. And a drain pipe system provided with an orifice.

According to a fourth aspect of the present invention, there is provided a drain pipe system according to any one of the first to third aspects, wherein the fluid number of the drain pipe is set to 1.0 or more. I do.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a drain pipe system according to the present invention will be described below with reference to the drawings. In the following embodiments, a case where the invention is applied to a drain pipe connecting an aftercooler and a condenser of a geothermal power plant will be described.

First Embodiment (FIG. 1) FIG. 1 is a system diagram showing a drain pipe system according to the present embodiment.

In the system shown in FIG. 1, the steam flowing into the aftercooler 11 through the steam / gas pipe 22,
Gas, water and the like are cooled by the water flowing through the cooling water pipe 13, and steam and the like are discharged to the atmosphere from the atmosphere discharge pipe 14 as a vent, and the drain is supplied to the condenser 16 via the drain pipe 15. It is supposed to be.

That is, the internal pressure of the aftercooler 11 is set to, for example, 1.08 kg / cm ² and the internal pressure of the condenser 16 is set to 0.136 kg / cm ² , respectively. Drain supply is performed to the 16 side via the drain pipe 5. The drain temperature was 68 ° C., and the drain flow rate was 850 Ton / Hr.

Under such a configuration, in the present embodiment, as shown in FIG. 1, the drain pipe 15 has a pipe portion 15a lower than the water level of the drain 17 in the condenser 16, and An air / water separator 18 is provided upstream of the pipe 15a.

The steam / water separator 18 has a steam / water separator tube 19 having a certain height, and a gas vent device tube 20 connected to the upper portion of the steam / water separator tube 19.
0 is connected to the atmosphere discharge pipe 14. The drain discharged from the aftercooler 11 flows into the steam separator 19 via the drain pipe 15, and is set so that the drain 17 is stored at a constant water level inside the drain 17. The contained gas is released to the atmosphere release pipe 14 through a gas release pipe 20 having the same pressure as the aftercooler 11. As a result, gas is not entrained in the U seal portion, and a liquid U seal is formed.

In the present embodiment, the size of the drain pipe 15 is set to a Froude number of 1.0 or more, whereby the diameter is set to, for example, 400 mm. Further, assuming that half of the area inside the drain pipe 15 is gas, the size of the degasser pipe 20 is 100 mm, the flow velocity in the pipe is 15 m / s,
The pressure loss is 0.01 kg / cm ² (gas release device tube 20
Is equivalent to a straight pipe length of 30 m).

In the system of the present embodiment, the U-water separation pipe 19 provided in the drain pipe 15
By the sealing function, the internal pressure of the aftercooler 11 and the internal pressure of the condenser 16 can be separated and the operation can be continued. In this case, in this embodiment, in order to obtain the U-seal function, the size of the drain pipe is set to be equal to or less than 0.3 by the conventional design method because the number of fluids of the drain pipe 15 is set to 1 or more. Compared with the case where a diameter of 600 mm is required.

Therefore, according to the present embodiment, the U-seal pipe can be secured without the necessity of employing a large-sized drain pipe on the assumption that the U-seal pipe is economically advantageous. In addition, a steam-water separation pipe 19 provided in the middle of the drain pipe 15
By storing the drain 17 in the tank, it is possible to prevent the U-seal from being broken due to pressure fluctuation in the cooler when the plant is started or suddenly.

Second Embodiment (FIG. 2) FIG. 2 is a system diagram showing a system according to the present embodiment.

In this embodiment, the aftercooler 11 and the condenser 16 for condensing the exhaust gas of the steam turbine whose internal pressure is lower than that of the aftercooler 11 are provided with a pipe portion 15a lower than the water level in the condenser 16. It is similar to the first embodiment in that the connection is made by a U-shaped drain pipe 15 and the drain is supplied from the aftercooler 11 to the condenser 16 through the drain pipe 15.

This embodiment is different from the first embodiment in that a certain amount or more of the drain 17 is always stored in the lower portion of the aftercooler 11 and the water level is set to be maintained.

According to the present embodiment, the drain 17 is guided from the lower part of the cooler through the drain pipe 15 to the condenser 16 while maintaining the water level in the aftercooler 11. That is, by maintaining the water level in the aftercooler 11, the structure is such that the gas in the aftercooler 11 is not drawn into the drain tube 15.

In the present embodiment, the size of the drain tube 15 is set to a Froude number of 1.0 or more, whereby the diameter is set to, for example, 400 mm. The steam conditions and the like are the same as in the first embodiment.

In the system according to this embodiment, the aftercooler 11 has a water level and the aftercooler 1
1 is prevented from being caught in the drain pipe 15, the liquid U can be used without having to employ a large-sized drain pipe.
A seal can be secured.

Third Embodiment (FIG. 3) FIG. 3 is a system diagram showing a system according to this embodiment.

In the present embodiment, the aftercooler 11 and the condenser 16 for condensing the steam turbine exhaust having a lower internal pressure than the aftercooler are provided with a pipe 15a having a pipe portion 15a lower than the water level in the condenser 16. The first embodiment is the same as the first embodiment in that the connection is made by a D-shaped drain pipe 15 and the drain is supplied from the aftercooler 11 to the condenser 16 through the drain pipe 15.

The present embodiment differs from the first embodiment in that an orifice 21 is provided at the inlet of the condenser of the drain pipe 15.

In this embodiment having such a configuration,
Since the orifice 21 is provided at the inlet of the condenser 16, when the drain from the aftercooler 11 passes through the drain pipe 15 to the condenser 16, when the pressure inside the aftercooler 11 fluctuates, or It functions as a pressure buffering member in an unstable pressure state when the plant is started. Therefore,
By controlling such that the U-seal water level does not decrease at the time of such plant start-up or sudden pressure fluctuations in the cooler, the resistance of the drain flow increases, and the liquid U-seal is maintained so as not to be broken. Is done.

Therefore, according to the present embodiment, the U-seal can be secured without the necessity of employing a large-sized drain pipe, assuming that the U-seal pipe is economically advantageous. There is a great advantage that the U seal can be prevented from being broken due to a pressure fluctuation in the cooler.

[0038]

As described in detail above, according to the present invention, an apparatus and a system which are advantageous in terms of cost and space in arrangement of equipment without requiring complicated equipment or equipment are provided. can do.

That is, according to the first aspect of the present invention, the gas caught in the cooler drain pipe from the cooler is separated into the drain and the gas by the steam separator, and the drain flows to the condenser by the pressure difference, and the gas is discharged to the condenser. By extracting from the upper part of the steam separator and connecting it to the discharge pipe or the cooler main body at the same pressure as the inside of the cooler, the liquid U seal can be formed without the gas being caught in the U seal part.

According to the second aspect of the present invention, the liquid U seal can be ensured without having the water level in the cooler main body and the gas in the cooler being caught in the drain pipe.

According to the third aspect of the present invention, since the resistance of the drain is increased by inserting an orifice into the inlet of the condenser on the secondary side of the U seal, pressure fluctuations such as pulsation in the cooler at the time of starting the plant or suddenly. The U seal water level does not drop due to
The seal can be prevented from being broken.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a configuration of a first embodiment of a drain pipe system according to the present invention.

FIG. 2 is a system diagram showing a configuration of a second embodiment of the drain pipe system according to the present invention.

FIG. 3 is a system diagram showing a configuration of a third embodiment of the drain pipe system according to the present invention.

FIG. 4 is a system diagram showing a configuration of an example of a conventional drain pipe system.

FIG. 5 is a system diagram showing a configuration of another example of a conventional drain pipe system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Aftercooler 12 Steam / gas pipe 13 Cooling water pipe 14 Atmospheric discharge pipe 15 Drain pipe 16 Condenser 17 Drain 18 Gas-water separator 19 Gas-water separator pipe 20 Gas vent pipe 21 Orifice

Claims (4)

[Claims] 1. A steam cooler for steam cooling provided in a steam turbine plant and a condenser for condensing steam turbine exhaust having a lower internal pressure than the cooler, a pipe section having a water level lower than the water level in the condenser. A drain pipe system for supplying a drain from the cooler to the condenser through the drain pipe, wherein a steam-water separator is provided in the middle of the drain pipe; Drain to the outside of the drain pipe. 2. A condenser for steam cooling provided in a steam turbine plant and a condenser for condensing steam turbine exhaust having a lower internal pressure than the cooler, a pipe section having a lower level than the water level in the condenser. A drain pipe system for supplying a drain from the cooler to the condenser through the drain pipe through the drain pipe, the lower part of the cooler always maintaining a predetermined or higher water level. A drain pipe system characterized in that the drain is stored in the drain pipe. 3. A cooler for cooling steam provided in a steam turbine plant and a condenser for condensing steam turbine exhaust having a lower internal pressure than the cooler, a pipe section having a lower level than the water level in the condenser. A drain pipe system for supplying a drain from the cooler to the condenser through the drain pipe, wherein an orifice is provided at a condenser inlet portion of the drain pipe. A drain pipe system characterized by the above-mentioned. 4. The drain pipe system according to claim 1, wherein a fluid number of the drain pipe is set to 1.0 or more.